TweetFollow Us on Twitter

June 94 - Somewhere in QuickTime

SOMEWHERE IN QUICKTIME

Basic Movie Playback Support

PETER HODDIE


Adding basic QuickTime movie playback support to most applications is simple, often just one day's work. Developers who want to do this turn first to Inside Macintosh: QuickTime , where it says to use a movie controller component. In Inside Macintosh: QuickTime Components,  you find some elementary movie controller code samples, followed by a large reference section. This is usually enough to get started, but there are a few common problems. This column addresses some of them, with special attention to compatibility with future QuickTime releases. It assumes you're familiar with basic QuickTime and movie controller concepts.

OPENMOVIEFILE
All QuickTime movie files contain a movie resource, usually stored in the file's resource fork, and the actual movie data, stored in the file's data fork. To support cross-platform QuickTime movies, QuickTime's Movie Toolbox also allows the movie resource to be stored in the data fork along with the movie's data. (To learn how this is done, see John Wang's Somewhere in QuickTime column in develop  Issue 17.) The usual sequence of calls to load a QuickTime movie from a file is: OpenMovieFile, NewMovieFromFile, CloseMovieFile.

In the common case of the movie resource stored in the resource fork, OpenMovieFile returns a file reference to the resource fork of the movie file, NewMovieFromFile loads the movie resource from that resource fork and creates a QuickTime movie, and CloseMovieFile closes the resource fork.

But if the movie was created on a computer running Microsoft Windows and QuickTime for Windows (using AdobeTM Premiere, for example), the file won't have a resource fork. Still, you can use the exact same sequence of calls. When OpenMovieFile is called, the file reference returned refers to the data fork; NewMovieFromFile loads the movie from the data fork, and CloseMovieFile closes the data fork.

Some developers don't use OpenMovieFile; they use FSpOpenResFile instead. While this works fine with movies made specifically for the Macintosh, it fails miserably otherwise. There's a sample movie with no resource fork, QuickBuck, on this issue's CD, so you can test this situation with your applications.

If you need to know whether OpenMovieFile opened the resource fork or the data fork, you can examine the file reference it returns, as follows:

pascal Boolean IsDataFork(short fileReference)
{
    FCBPBRec    anFCB;
    Str63       fName;

    anFCB.ioVRefNum = 0;
    anFCB.ioRefNum = fileReference;
    anFCB.ioFCBIndx = 0;
    fName[0] = 0;
    anFCB.ioNamePtr = (StringPtr)fName;

    if (PBGetFCBInfoSync(&anFCB) != noErr)
        return false;

    return (anFCB.ioFCBFlags & 0x0200) == 0;
}

NEWMOVIECONTROLLER
When you need a user interface for playing a movie, you should use NewMovieController to create a movie controller appropriate for use with that movie.

A common mistake is to instead use the Component Manager routine FindNextComponent or OpenDefaultComponent to locate a movie controller. This finds the first movie controller in the system's list of registered components. QuickTime has always contained only one movie controller, so this worked fine. However, future versions of QuickTime will almost certainly include other movie controllers, so the first one isn't necessarily the most appropriate one.

To help track down those offending applications that don't use NewMovieController, there's a system extension on this issue's CD which contains a different movie controller. You'll also find a movie, Other Controller Movie, that should  invoke the sample movie controller. If any other movie invokes the sample movie controller, or if Other Controller Movie invokes the standard movie controller, the application you're testing isn't using NewMovieController. This will cause undesirable results in the not-so-distant future.

UPDATE EVENTS
If you use a movie controller in the recommended way (that is, you allow all events to be filtered through MCIsPlayerEvent), it updates all areas of the window covered by the movie and the movie's controls. Usually that's all a window contains, so all update events are completely handled by the movie controller. This works so well that some developers actually forget to support update events at all.

Unfortunately, it's not always so simple. QuickTime movies aren't always rectangular. If the movie is round and the window is rectangular (as in Figure 1), there are areas in the window that are not covered by the movie or the movie controls. Any update events in these areas are the responsibility of the application. [IMAGE 022-025_Somewhere_in_QT_2.GIF]

Figure 1. A nonrectangular movie

For applications using MCIsPlayerEvent, handling update events is easy:

BeginUpdate(theWindow);
EraseRect(&theWindow->portRect);
EndUpdate(theWindow);

This sample code erases all areas of the window besides the movie and its controls. Normally, erasing the portRect of the window would erase the entire window, but MCIsPlayerEvent sets the update region to just the areas it didn't already handle.

If you don't handle update events, things are even worse than you might think. The window won't be updated correctly, but more important, the operating system will keep generating new update events. Update events have a higher priority than idle events, so the system will never generate idle events -- the movie will receive no time to play.

A sample round movie is provided on this issue's CD so that you can test your handling of update events.

KEYSTROKES
The standard movie controller provides for extensive keyboard control from the user but ignores keystrokes by default. They can be enabled with a single line of code:

MCDoAction(mc, mcActionSetKeysEnabled, (void *)true);

You might want to enable keystrokes only under certain circumstances. For example, a word processor might allow the movie controller to receive keystrokes only when a movie is selected. You can use the mcActionSetKeysEnabled action to enable and disable keystrokes as necessary.

MOUSE CLICKS
All applications that use the standard movie controller pass mouse clicks on to the controller. But not all applications pass mouse clicks made on the movie itself. Failure to pass such clicks will cause problems with any future movie controllers that allow the user to interact directly with the contents of the movie. For example, a movie controller might allow the user to pan around the image by dragging on the movie; if mouse clicks aren't passed through, using either MCClick or MCIsPlayerEvent, this feature won't work.

MOVIE CONTROLLER HELP
The standard Apple movie controller is simple enough for most people to understand immediately, but it supports help balloons anyway (future movie controllers might be less obvious). If Balloon Help is turned on, the standard movie controller automatically displays help for its various controls, as well as for the QuickTime movie itself. You don't have to do anything at all for this to work.

A problem can arise if your application puts up its own help balloons. Since QuickTime movies are often embedded in a larger document, the help balloons may conflict. The result is that the movie controller's help balloon alternates with the application's help balloon. (Use Balloon Help with the Scrapbook desk accessory included with QuickTime to see what this looks like.)

The preferred solution is to stop the application from displaying a help balloon when the cursor is over a QuickTime movie or movie control. It's easy to tell whether a given point in a window intersects the movie:

Boolean PointInMovieController(MovieController
        mc, WindowPtr w, Point where)
{
    RgnHandle   rgn;
    Boolean     result = false;

    rgn = MCGetWindowRgn(mc, w);
    if (rgn != nil) {
        result = PtInRgn(where, rgn);
        DisposeRgn(rgn);
    }
    return result;
}

A second solution is to stop the movie controller from displaying its help balloons -- necessary if you want to display your own help for QuickTime movies. To do this, install an action filter on the movie controller. Every action that occurs in the movie controller (play, step, update, key down, and so on) is passed through a single filter function. Through this filter, an application can gain access to all activity that occurs in the movie controller.

The MegaMovies application on this issue's CD provides a window that displays events that pass through the action filter. The action of interest is mcActionShowBalloon. When this action is sent, QuickTime is about to put up a new help balloon. One of the parameters passed to the action filter is a pointer to a Boolean. The filter can set this Boolean to false to tell the movie controller not to show a balloon. The following code fragments show how to install a simple action filter to prevent the movie controller from displaying help balloons.

pascal Boolean noBalloonsActionFilter 
                (MovieController mc, short action, 
                 void *params, long refCon)
{
    if (action == mcActionShowBalloon)
        *(Boolean *)params = false;
    return false;
}

. . .
MCSetActionFilterWithRefCon(mc, 
        &noBalloonsActionFilter, 0);

CURSOR SHAPE
Many applications change the shape of the cursor depending on what it's currently over. The standard movie controller never changes the cursor, but other movie controllers might want to. Unfortunately, many applications need to control the cursor themselves -- when a movie controller changes the cursor, these applications change it back immediately.

A simple solution is for applications to change the cursor only when it's first placed over a movie. (To determine whether a point is over the movie, use PointInMovieController.) After that, let the movie controller control the cursor until it exits the area over the movie. To give the movie controller the opportunity to change the cursor's shape, you must call either MCIsPlayerEvent or MCIdle frequently while the cursor is over the movie, even if the movie is stopped. The sample movie controller on this issue's CD changes the cursor when it's over the movie, providing an easy way to debug such a scheme.

WINDOW ALIGNMENT
A simple way to improve a QuickTime movie's playback performance is to ensure that the movie is at a good location on the screen. The exact definition of a "good location" varies, based on the screen depth and the processor. A typical good location is one where the first pixel of each scan line begins on a long-word boundary. This allows the decompressors to write data in the most efficientway. On slower machines, proper placement can provide the necessary performance improvement to deliver smooth playback.

Fortunately, applications don't have to understand the details of how to find a good location. QuickTime's Image Compression Manager provides routines to position a window at these locations. When you create a window, you can use AlignWindow to move it to a good location before making it visible. If a window is to be moved, AlignScreenRect will modify the chosen location to make it a good location. When the user drags a window, call DragAlignedWindow instead of DragWindow to place the window in a good location. Examples of these calls are shown below.

WindowPtr   w;
Movie       m;
Rect            r;

// Code to create a properly aligned window.
w = GetNewCWindow(128, nil, (WindowPtr)-1);
m = getMovie();
GetMovieBox(m, &r);
AlignWindow(w, false, &r, nil);

// Code to drag a window with a movie in it and
// keep the window aligned properly.
GetMovieBox(m, &r);
DragAlignedWindow(w, theEvent.where, nil, &r, nil);

These alignment routines were added in QuickTime 1.5, so make sure that QuickTime 1.5 or later is installed before you call them.

MOVIE CONTROLLER EDITING
The standard movie controller supports the editing commands Undo, Cut, Copy, Paste, and Clear, but this functionality is turned off by default. To turn it on, call MCEnableEditing as follows:

MCEnableEditing(mc, true);

You can then use movie controller routines to implement editing:

Movie       m = nil;

switch (editMenuSelection) {
    case menuUndo:      MCUndo(mc);
                            break;
    case menuCut:       m = MCCut(mc);
                            break;
    case menuCopy:      m = MCCopy(mc);
                            break;
    case menuPaste: MCPaste(mc, nil);

Now you have to enable and disable the various menu items. You could call MCGetControllerInfo, which returns a long word of flags indicating, among other things, which Edit menu items should be enabled.With QuickTime 1.5, there's an easier way: call MCSetUpEditMenu, and the movie controller will enable and disable the items in the Edit menu for you.

MCSetUpEditMenu(mc, theEvent.modifiers, editMenuHandle);
[IMAGE 022-025_Somewhere_in_QT_3.GIF]

Standard [IMAGE 022-025_Somewhere_in_QT_4.GIF]

Modified


This routine will even change the menu contents if appropriate. For example, Undo becomes Undo Paste if the last movie controller action was Paste; after Undo Paste is chosen, it becomes Redo Paste. What's more, if the user holds down modifier keys when pulling down a menu, other commands change as well. For example, holding down the Option key changes Paste to Add and Clear to Trim. (See Figure 2.)

Figure 2. Standard and modified Edit menus

MCSetUpEditMenu assumes the Edit menu is arranged in the standard way. If yours is nonstandard, you'll need to use MCGetMenuString to obtain the appropriate text for each standard Edit command, and then enable and disable the menu items according to the information from MCGetControllerInfo.

JUST DO IT
It's so easy to add movie playback support that it's often well worth the effort. As long as you keep these few simple things in mind, you shouldn't have any problems, even with future versions of QuickTime.

PETER HODDIE writes code to introduce hard-to-find bugs into QuickTime. In his spare time he writes code to introduce even harder-to-find bugs into QuickTime. *

Thanks to Jim Batson, Ken Doyle, and John Wang for reviewing this column. *

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

GraphicConverter 10.5.1 - $39.95
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more
Delicious Library 3.7 - Import, browse a...
Delicious Library allows you to import, browse, and share all your books, movies, music, and video games with Delicious Library. Run your very own library from your home or office using our... Read more
Adobe Animate CC 2017 18.0.0.107 - Anima...
Animate CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Flash Professional customer). Animate CC 2018 (was Flash CC) lets you... Read more
Adobe After Effects CC 2018 15.0 - Creat...
After Effects CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). The new, more connected After Effects CC... Read more
Adobe Premiere Pro CC 2018 12.0.0 - Digi...
Premiere Pro CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Premiere Pro customer). Adobe Premiere Pro CC 2018 lets you edit... Read more
Alarm Clock Pro 10.3 - $19.95
Alarm Clock Pro isn't just an ordinary alarm clock. Use it to wake you up in the morning, send and compose e-mails, remind you of appointments, randomize the iTunes selection, control an internet... Read more
Adobe Lightroom 20170919-1412-ccb76bd] -...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
Adobe Illustrator CC 2018 22.0.0 - Profe...
Illustrator CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Illustrator customer). Adobe Illustrator CC 2018 is the industry... Read more
Hopper Disassembler 4.3.0- - Binary disa...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
Adobe InDesign CC 2018 13.0.0.125 - Prof...
InDesign CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous InDesign customer). Adobe InDesign CC 2018 is part of Creative Cloud.... Read more

ICEY (Games)
ICEY 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ICEY is a 2D side-scrolling action game. As you follow the narrator's omnipresent voice, you will see through ICEY's eyes and learn the... | Read more »
The best new games we played this week -...
We've made it, folks. Another weekend is upon us. It's time to sit back and relax with the best new releases of the week. Puzzles, strategy RPGs, and arcade games abound this week. There's a lot of quality stuff to unpack this week, so let's hop... | Read more »
Wheels of Aurelia (Games)
Wheels of Aurelia 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: | Read more »
Halcyon 6: Starbase Commander guide - ti...
Halcyon 6 is a well-loved indie RPG with stellar tactical combat and some pretty good writing, too. It's now landed on the App Store, so mobile fans, if you're itching for a good intergalactic adventure, here's your game. Being a strategy RPG, the... | Read more »
Game of Thrones: Conquest guide - how to...
Fans of base building games might be excited to know that yet another entry in the genre has materialized - Game of Thrones: Conquest. Yes, you can now join the many kingdoms of the famed book series, or create your own, as you try to conquer... | Read more »
Halcyon 6: Starbase Commander (Games)
Halcyon 6: Starbase Commander 1.4.2.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.4.2.0 (iTunes) Description: An epic space strategy RPG with base building, deep tactical combat, crew management, alien diplomacy,... | Read more »
Legacy of Discord celebrates its 1 year...
It’s been a thrilling first year for fans of Legacy of Discord, the stunning PvP dungeon-crawling ARPG from YOOZOO Games, and now it’s time to celebrate the game’s first anniversary. The developers are amping up the festivities with some exciting... | Read more »
3 reasons to play Thunder Armada - the n...
The bygone days of the Battleship board game might have past, but naval combat simulators still find an audience on mobile. Thunder Armada is Chinese developer Chyogames latest entry into the genre, drawing inspiration from the explosive exchanges... | Read more »
Experience a full 3D fantasy MMORPG, as...
Those hoping to sink their teeth into a meaty hack and slash RPG that encourages you to fight with others might want to check out EZFun’s new Eternity Guardians. Available to download for iOS and Android, Eternity Guardians is an MMORPG that lets... | Read more »
Warhammer Quest 2 (Games)
Warhammer Quest 2 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon adventures in the Warhammer World are back! | Read more »

Price Scanner via MacPrices.net

12″ iPad Pros on sale for $50 off MSRP, no ta...
Adorama has 12″ iPad Pros on sale today for $50 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: – 12″ 64GB iPad Pro: $749, save $50 – 12″ 256GB iPad Pro: $899, save $50... Read more
9″ iPads on sale for $30 off, starting at $29...
MacMall has 9″ iPads on sale for $30 off including free shipping: – 9″ 32GB iPad: $299 – 9″ 128GB iPad: $399 Read more
Apple restocks full line of refurbished 13″ M...
Apple has restocked a full line of Apple Certified Refurbished 2017 13″ MacBook Pros for $200-$300 off MSRP. A standard Apple one-year warranty is included with each MacBook, and shipping is free.... Read more
13″ 3.1GHz/256GB MacBook Pro on sale for $167...
Amazon has the 2017 13″ 3.1GHz/256GB Space Gray MacBook Pro on sale today for $121 off MSRP including free shipping: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (MPXV2LL/A): $1678 $121 off MSRP Keep an... Read more
13″ MacBook Pros on sale for up to $120 off M...
B&H Photo has 2017 13″ MacBook Pros in stock today and on sale for up to $120 off MSRP, each including free shipping plus NY & NJ sales tax only: – 13-inch 2.3GHz/128GB Space Gray MacBook... Read more
15″ MacBook Pros on sale for up to $200 off M...
B&H Photo has 15″ MacBook Pros on sale for up to $200 off MSRP. Shipping is free, and B&H charges sales tax in NY & NJ only: – 15″ 2.8GHz MacBook Pro Space Gray (MPTR2LL/A): $2249, $150... Read more
Roundup of Apple Certified Refurbished iMacs,...
Apple has a full line of Certified Refurbished 2017 21″ and 27″ iMacs available starting at $1019 and ranging up to $350 off original MSRP. Apple’s one-year warranty is standard, and shipping is free... Read more
Sale! 27″ 3.8GHz 5K iMac for $2098, save $201...
Amazon has the 27″ 3.8GHz 5K iMac (MNED2LL/A) on sale today for $2098 including free shipping. Their price is $201 off MSRP, and it’s the lowest price available for this model (Apple’s $1949... Read more
Sale! 10″ Apple WiFi iPad Pros for up to $100...
B&H Photo has 10.5″ WiFi iPad Pros in stock today and on sale for $50-$100 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB iPad Pro: $... Read more
Apple iMacs on sale for up to $130 off MSRP w...
B&H Photo has 21-inch and 27-inch iMacs in stock and on sale for up to $130 off MSRP including free shipping. B&H charges sales tax in NY & NJ only: – 27″ 3.8GHz iMac (MNED2LL/A): $2179 $... Read more

Jobs Board

Engineering Manager, *Apple* Retail Enginee...
# Engineering Manager, Apple Retail Engineering Job Number: 58139948 Santa Clara Valley, California, United States Posted: 20-Oct-2017 Weekly Hours: 40.00 **Job Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Commerce Engineer, *Apple* Media Products -...
Commerce Engineer, Apple Media Products (New York City) Job Number: 113028813New York City, New York, United StatesPosted: Sep. 20, 2017Weekly Hours: 40.00 Job Read more
US- *Apple* Store Leader Program - Apple (Un...
US- Apple Store Leader Program Job Number: VariousUnited StatesPosted: Oct. 19, 2017Retail Store Job Summary Learn and grow as you explore the art of leadership at Read more
Product Manager - *Apple* Pay on the *Appl...
Job Summary Apple is looking for a talented product manager to drive the expansion of Apple Pay on the Apple Online Store. This position includes a unique Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.